1. Field of the Invention
The present invention relates to image-display game machines, image-display game systems, and information storage media storing game programs therefor. More specifically, the present invention relates to video game machines and portable game machines capable of simulating the capturing, training, and exchanging characters including those which appear to be monsters, and an information storage medium storing a game program therefor. Those characters are additionally provided with property data depending on time or time zone.
2. Description of the Background Art
Conventionally, video game machines adopting time-varying factors are disclosed in Japanese Laying-Open Publications (examined Patent Publications) No. 7-98104 (hereinafter referred to as "prior art 1"), No. 7-98105 (hereinafter referred to as "prior art 2"), and No. 7-98106 (hereinafter referred to as "prior art 3"). According to each of these prior arts 1, 2, and 3, a calendar timer is provided in a game machine cartridge for carrying out a predetermined event on a predetermined date or day of the week.
In addition to the above prior art, a game referred to as "Pocket Monster (four versions of red, green, blue, and yellow)" (trade name; hereinafter referred to as "prior art 4") which is designed and marketed by the assignee of applicants is available. The prior art 4 is a type of game capturing, training, and exchanging characters (hereinafter referred to as either pocket monsters or characters). For each version of the game, the appearance probability of a pocket monster (hereinafter shortened as "Pokemon", as required) is set differently. A player can capture or collect the maximum number of monsters by exchanging their monsters therebetween after playing each version of the game.
By referring to a block diagram shown in FIG. 12, the structure of the conventional image-display game machine according to the prior art 4 is described. A conventional image-display game machine GBC is roughly classified into a program source 100C and a game machine 200. The program source 100C stores information such as programs necessary for executing the image-display game on the game machine 200 and is detachably connected to the game machine 200.
The program source 100C is preferably structured in a form of cartridge including a ROM 11C, a RAM 12C, a memory bank controller 15, and a connector 13. The ROM 11C is implemented by non-volatile memory such as ROM, flash memory, and EEPROM to fixedly store the game program. The ROM 11C stores programs required by the contents of the game. If the game is a type of capturing and training characters such as monsters, for example, the stored programs are a capturing program and a training program. The ROM 11C also stores dot data for displaying each monster as an image and further stores a program for exchanging data, as required, among other game machines 200.
The RAM 12C is implemented by readable/writable memory, typified by RAM, and includes a memory region for storing a plurality of property data items for each type of character obtained in the course of playing the game.
The memory bank controller 15 divides a memory chunk of the ROM 11C into a plurality of banks when the memory chunk is too large for an address bus to address, and generates bank data for the higher address in the ROM 11C and for addressing a memory chunk in the RAM 12C. The ROM 11C, RAM 12C, and memory bank controller 15 are connected to the game machine 200 via the connector 13 in a detachable manner.
The game machine 200 is mainly structured by an operation switch portion 22, a central processing unit (CPU) 23, a connector 24, a RAM 25, a display controller 26, a liquid crystal display (LCD) 27, an interface 28, and a connector 29. The RAM 25 and the display controller 26 are connected to the CPU 23. The RAM 25 is working memory that temporarily stores data necessary for processing during the game. The LCD 27 is connected to the display controller 26.
Further, the CPU 23 is connected to the connector 29 through the interface circuit 28. The connector 29 is connected to another connector 29 of a separate game machine 200 via a cable when the player exchanges the obtained characters such as monsters with another player who is an owner of another game machine 200. Note that the CPU 23 is connected with the program source 100C through the connector 24.
Next, by referring to FIG. 13, the structure of a memory region of the RAM 12C is described in detail. The memory region of the RAM 12C includes an obtained Pokemon data region DAamC and an environmental data region DoC. The obtained Pokemon data region DaamC stores data that defines each of the obtained game characters, or Pokemons, and properties thereof. Each of the obtained Pokemons is recorded and identified as any of records R1 to RN (where N is a natural number). Each record R has fields I1 to I9 for each storing item that defines the obtained Pokemon.
In the field I1, a monster code (Pokemon number) assigned for each type of Pokemon is stored.
In the field I2, hit points (HP) possessed by the Pokemon are stored.
In the field I3, experience points possessed by the Pokemon are stored.
In the field I4, a level of the Pokemon is stored.
In the field I5, a status of the Pokemon is stored.
In the field I6, technique (possible attack) data of the Pokemon is stored.
In the field I7, an ID showing a player is stored.
In the field I8, values indicating Pokemon's ability such as an attack power, a defense power, a special attack power, a special defense power, and quickness are stored.
The field I9 is a spare field for storing data other than the above items stored in the fields I1 to I8.
Note that the data stored in the above fields I2, I3, I4, I5, I6, I8 and I9 are updated with the progress of the game.
As described above, each obtained Pokemon is defined by any of the records R1 to RN, and the properties thereof are defined by the fields I1 to I9. That is to say, a property of an arbitrary obtained Pokemon is represented by P (Rn, Im), where n is a natural number equal to or smaller than N, and m is a natural number equal to or smaller than 9. The property data stored in the fields I1 to I9, however, does not have a time-varying factor such as time or time zone giving an unexpectance to the game.
In the environmental data region DoC, environmental data required for the progress of the game are stored. Such data includes a location, a time when the game is played, a name of a player, and the like. The data stored in the environmental data region Doc does not have a time-varying factor such as time or time zone giving an unexpectance to the game.
As described in the foregoing, according to the prior art 1, 2, and 3, a player just enjoys a predetermined event carried out by a program on a predetermined date or day of the week but can not enjoy capturing or exchanging the characters. Accordingly, once the player learned what event is carried out on what time, the unexpectancy of the event is dismissed. Thus, the player soon becomes not interested in the game.
On the other hand, compared with the prior art 1, 2, and 3, the player can enjoy the game in the prior art 4 relatively longer without losing his/her interest. Further, it is helpful to deepen communications and cultivate friendships through exchanging the monsters with friends. However, also in the prior art 4, the player will get tired of the game as time passes.
A main object of the present invention is to provide an image-display game machine and an information storage medium storing a game program therefor that diversifies contents of the game and increases amusement so as to stir up aspirations of the player to challenge the game many times by introducing the time-varying factor. Another object is to provide an image-display game machine and an information storage medium storing a game program therefor that provides more fun by changing property data of characters such as monsters based on the thus introduced time-varying factor to further diversify the developments in the game depending on a player's knowledge and thinking.